1. Field of the Invention
The present invention relates to a disk cartridge having a cartridge housing in which a disk-like recording medium such as an optical disk, a magneto-optical disk and a magnetic disk is stored in a disk compartment so as to become freely rotatable, and particularly to a disk cartridge in which a pair of shutter members are opened and closed to open and close an opening portion by rotating a middle shell which forms a disk compartment between it and an upper shell or a lower shell and part of a disk-like recording medium is exposed from the opening portion when the opening portion is opened.
2. Description of the Related Art
As a disk cartridge in which a disk-like recording medium in and/or from which audio information, video information or information such as computer data can be recorded and/or reproduced is rotatably stored in a cartridge housing, there is known a disk cartridge having an arrangement shown in FIG. 1, for example. This disk cartridge 1 is a disk cartridge incorporating therein a write once magneto-optical disk 4 in which a user can record and write information such as computer data later on. This disk cartridge has an outward shape shown in FIG. 1.
As shown in FIG. 1, this disk cartridge 1 includes a cartridge housing 2 comprised of a pair of an upper shell 2a and a lower shell 2b, a magneto-optical disk 4 rotatably stored within a disk compartment 3 of this cartridge housing, and the like. The cartridge housing 2 has on its upper and lower surfaces defined an upper and lower opening portion 5 which is extended from the central portion to one side. This opening portion 5 can be opened and closed by a shutter member 6 which can be slid along one side. Reference numeral 6a designates a presser member which can prevent the tip end portion of the shutter member 6 from being extracted.
A disk-like metal center hub 7 is provided at the central portion of the magneto-optical disk 4. This center hub 7 is disposed at the position opposing to the inner end portion of the opening portion 5, i.e., at substantially the central portion of the cartridge housing 2. A turntable provided on an information recording and reproducing apparatus body side is mounted on this center hub 7 and the magneto-optical disk is fixed to the center hub by chucking the turntable, whereby the magneto-optical disk 4 is rotated at a predetermined velocity (e.g., constant linear velocity). In this case, an information signal is recorded on or reproduced from the magneto-optical disk 4 by an action of a magneto-optical pickup device whose head portion is inserted into the opening portion 5.
However, in the related-art disk cartridge 1 having the above arrangement, the shutter member 6 which opens and closes the opening portion 5 has a U-like shaped cross-section. This shutter member 6 is fitted into one side of the cartridge housing 2 and the shutter member 6 is slid along one side of the cartridge housing 2 to thereby open and close the opening portion 5. For this reason, a disk recording and reproducing apparatus side requires a shutter opening and closing mechanism for sliding the shutter member 6 to open and close the opening portion 5, and the related-art shutter opening and closing mechanism is relatively complicated in structure. Further, it is unavoidable that a large space is produced between the cartridge housing 2 and the shutter member 6, and therefore the disk cartridge 1 cannot be prevented from being smudged by very small dusts and the like.
In recent years, in the stream in which an optical disk is increasing its storage capacity/increasing its recording density, a recording pattern is becoming narrower in pitch and is increasing a linear density. When a recording surface of an optical disk or a magneto-optical disk is smudged by dusts, read or write beam is shielded or when the information recording surface of the optical disk is damaged by scratches, information cannot be read or written normally. For this reason, in the related-art disk cartridge 1, as shown in FIG. 1, the shutter member 6 having substantially the U-like shaped cross-section is attached to one side of the cartridge housing 2 so as to become slidable and is slid along one side of the cartridge housing 2 to thereby open and close the opening portion 5 so that the information recording surface of the optical disk or the like can be protected.
However, as the optical disk is further increasing a storage capacity/increasing a recording density, very small dusts which are not so influential in the related art becomes more influential in reading and writing of data. Therefore, the shutter member having the above U-like shape cannot prevent the disk cartridge 1 from being smudged by very small dusts. In this case, when the information recording surface of the magneto-optical disk 4 is smudged by very small dusts entered into the cartridge housing 2, the information recording surface of the magneto-optical disk is damaged by dusts so that information cannot be read out from and written in the magneto-optical disk normally.
In the above disk cartridge 1 according to the related art, the shutter member 6 is located on the disk cartridge 1 at its position in which users can easily touch the shutter member 6. There is then the risk that a user will slide the shutter member 6 to open the opening portion 5 by mistake. In addition, since the shutter member 6 is linearly slid along one side of the cartridge housing 2, there arises a problem that the surface area of the cartridge housing 2 cannot be reduced.
In view of the aforesaid aspect, it is an object of the present invention to provide a disk cartridge in which an opening portion in and from which a turntable, an optical head and the like are inserted and ejected is widened as much as possible so that two optical heads can be used simultaneously.
It is another object of the present invention to provide a disk cartridge in which an optical head can approach the innermost periphery of a disk-like recording medium with high efficiency.
It is a further object of the present invention to provide a disk cartridge in which a middle shell is made rotatable, a pair of shutter members are opened and closed based on the rotation of this middle shell and end faces of the pair of shutter members are contacted with each other so that the pair of shutter members can be opened and closed smoothly and reliably.
It is yet a further object of the present invention to provide a disk cartridge in which a space between the pair of shutter members is reduced as much as possible by pressing the pair of shutter members against each other so that a dustproof property and an airtightness of the large opening portion can be improved.
010 According to an aspect of the present invention, there is provided a disk cartridge which is comprised of a cartridge housing in which a disk compartment is formed by overlapping a pair of shells, a disk-like recording medium rotatably stored within the disk compartment and a pair of shutter members rotatably attached to the cartridge housing and exposing part of the disk-like recording medium by opening and closing an opening portion provided on the cartridge housing when they are moved, wherein the opening portion is extended in the diametrical direction of the disk-like recording medium through the central portion of the lower shell or the upper shell.
According to another aspect of the present invention, in the disk cartridge, the cartridge housing includes a middle shell rotatably supported by the upper shell and the lower shell and the opening portion is formed through the middle shell and the lower shell or the upper shell.
According to still another aspect of the present invention, in the disk cartridge, the pair of shutter members are comprised of a combination of a pair of substantially semicircular same plate materials, the pair of shutter members are symmetrically disposed on one surface of the middle shell across the opening portion, the guide groove is provided on one side portion of a chord side in each of the shutter members and a shaft portion provided on the other side portion of the chord side is rotatably supported to the middle shell.
According to a further aspect of the present invention, in the disk cartridge, a pair of guide grooves are provided on one of the pair of shutter members and the cartridge housing, a pair of operation convex portions which are slidably engaged with the guide grooves are provided on the other of the pair of shutter members and the cartridge housing, the guide grooves are moved along the operation convex portions based on the rotation of the middle shell, whereby the pair of shutter members are enabled to open and close the opening portion.
In accordance with a further aspect of the present invention, there is provided a disk cartridge which is comprised of a cartridge housing in which a disk compartment is formed within an upper shell and a middle shell or the middle shell and a lower shell by overlapping the upper shell, the middle shell and the lower shell and in which the middle shell is rotatably supported by the upper shell and the lower shell, a disk-like recording medium is stored within the disk compartment so as to become freely rotatable, a pair of shutter members are attached to the middle shell in such a manner that they can be moved in the flat surface direction on the same plane and a shutter opening and closing mechanism for tightly closing the opening portion provided on the cartridge housing and from which part of the disk-like recording medium is exposed by moving the pair of shutter members based on the rotation of the middle shell such that end faces of the pair of shutter members are pressed against each other.
In accordance with yet a further aspect of the present invention, in the disk cartridge, the shutter opening and closing mechanism includes a pair of guide grooves provided on one of the pair of shutter members and the cartridge housing, a pair of operational convex portions provided on the other of the pair of shutter members and the cartridge housing and which are slidably engaged with the guide grooves and the pair of shutter members are enabled to open and close the open and close portion by moving the guide grooves along the operational convex portions based on the rotation of the middle shell.
In accordance with yet a further aspect of the present invention, in the disk cartridge, the pair of guide grooves include resilient members for imparting spring force to the pair of operational convexs such that the pair of shutter members are spring-biased in the flat surface direction when the pair of shutter members are closed.
In accordance with still a further aspect of the present invention, in the disk cartridge, the pair of shutter members are comprised of a combination of a pair of substantially semicircular same plate-like materials, the pair of shutter members are symmetrically disposed on one surface side of the middle shell across the opening portion, the guide grooves are provided on one side portions of chord sides of the respective shutter members and pivots provided on the other side portions of the chord sides are supported to the middle shell so as to become freely rotatable.
14 With the above arrangement, in the disk cartridge including the cartridge housing having the disk compartment, the disk-like recording medium and the pair of shutter members, since the opening portion is extended in the diametrical direction of the disk-like recording medium through the central portion of the cartridge housing, two recording and/or reproducing head portions can simultaneously be inserted into the opening portion so that two recording and/or reproducing operations can be executed at the same time. Furthermore, the two recording and/or reproducing head portions can approach the innermost periphery of the disk-like recording medium and therefore, the disk cartridge can approach the innermost periphery of the disk-like recording medium with high efficiency.
According to the disk cartridge of the present invention, since the cartridge housing includes the middle shell in addition to the upper shell and the lower shell, the middle shell is rotatably supported by the upper shell and the lower shell and the opening portion is provided through the middle shell and the upper shell or the lower shell, there can be formed the opening portion into and from which two recording and/or reproducing head portions can be inserted and ejected simultaneously, and the opening portion can be opened and closed by the pair of shutter members.
16 According to the disk cartridge of the present invention, since the pair of shutter members are comprised of the combination of two substantially semicircular same plate materials, the pair of shutter members are symmetrically disposed across the opening portion, the guide grooves are provided on one side portions of the respective shutter members, the pivots are provided on the other side portions and the pivots are supported to the middle shell so as to become freely rotatable, the opening portion of the wide range can be opened and closed while the areas of the shutter members can be reduced. Therefore, the efficiency with which the opening portion is opened and closed can be increased, and the whole of the disk cartridge can be made compact and thin.
Further, according to the disk cartridge of the present invention, since the pair of guide grooves are provided on one of the pair of shutter members and the cartridge housing, the pair of operational convexs are provided on the other of the pair of guide grooves and the guide grooves are moved along the operational convexs based on the rotation of the middle shell, the pair of shutter members can be moved with high reliability so that the opening portion can be opened and closed smoothly and reliably.
Further, according to the disk cartridge of the present invention, in the disk cartridge comprising the cartridge housing having the disk compartment, the disk-like recording medium and the pair of shutter members, since the disk cartridge includes the shutter opening and closing mechanism for moving the pair of shutter members based on the rotation of the middle shell so that the end faces of the pair of shutter members are pressed against each other, the pair of shutter members can be contacted with each other reliably and strongly by rotating the middle shell. Therefore, the disk compartment can be prevented from being smudged by very small dusts and the like by reducing the space between the pair of shutter members and the cartridge housing. Hence, the dustproof property of the cartridge housing can be improved. Moreover, the disk cartridge can be reduced in thickness and improved in space factor so that the whole of the disk cartridge can be made compact and thin.
Further, according to the disk cartridge of the present invention, since the pair of operational convexs are moved along the pair of guide grooves based on the rotation of the middle shell, the pair of shutter members can be rotated smoothly and reliably.
Further, according to the disk cartridge of the present invention, since the shutter open and close mechanism presses the pair of shutter members, the two shutter members can be closely contacted with each other so that the dustproof property of the cartridge housing can be improved.
Furthermore, according to the disk cartridge of the present invention, since the pair of shutter members are comprised of a combination of two substantially semicircular same plate materials and the pair of shutter members are symmetrically disposed across the opening portion, the pair of shutter members can be operated with high reliability. Therefore, the opening portion can be opened and closed smoothly and reliably, and the whole of the disk cartridge can be made compact and thin.